Increasingly, explosives and other chemical warfare agents have become paramount threats to screen for in airports and government buildings. With access to plastic explosives and skillful disguising of weapons and explosive devices as ordinary, innocuous objects, terrorists need to be identified from the general passengers boarding aircraft or entering government buildings. It is known that certain explosive materials are inherently sticky, such as C-4 (a RDX based explosive) and can be removed from luggage or objects by physically touching (wiping) a sampling trap across the surface and then inserting the sampling trap in a detector such as an ion mobility spectrometer for analysis. Screening of people is a more difficult challenge since the above screening technique used on luggage is too intrusive and may violate human rights. A more socially acceptable screening method is to collect the chemical particle or vapor on a sampling trap without contacting the person.
By deploying the trace detection portal systems into airport check points, non-contact detection of explosives from airline passengers has gradually become possible. Currently, the trace detection portal systems are under some pressure to improve the efficiency of dislodging and collecting explosive particles from human body. In this invention, we describe a sample collection/detection method that could release and collect residues of explosives and other chemicals more effectively. Instead of using a large scale air handling system to release, collect, transport samples to the detection system as those used in trace detection portals, a sampling system in close proximity to the target area such as a handheld “wand” is described herein for screening chemical residues on the human body.
The concept of a using a handheld “wand” is a well accepted concept at security check points. Handheld metal detectors are still the best way to search for weapons on selectees when they cause an alarm at the walkthrough metal detector. This invention describes a handheld wand that can be used to confirm an alarm from the trace detection portal systems. In addition, flexibility and portability of the handheld wand will extend its application to broader security related areas, especially where a trace detection portal is not available. The handheld wand can be used as an intermediate step before a complete manual search is performed. Additionally, the handheld wand can be combined with multiple detectors for searching multiple threats. An exhaustive search for multiple threats can save valuable time and effort.